If the regular season came to a close today, both the Tampa Bay Rays and Oakland Athletics would qualify for the playoffs. But this is baseball, where September matters. Nothing is guaranteed.

While the Rays take 12-1 odds on the MLB futures into September, and the A’s have 14-1 odds of their own, the fact that so many wild card contenders have collapsed down the stretch in the past should leave fans of both squads leery about fall. The hard part is not over.

It starts this weekend, when the two clubs collide on the moneyline in a three-game set in Oakland. They’ll be fighting for every advantage they can get, even if just for insurance. While it’s certainly possible that both glide into the playoffs come October, the fact that it’s gone so wrong for so many other teams recently means they can’t take any chances. Now, in a season where every game matters, this weekend matters even more.

Although it’s reasonable that not only could the A’s and Rays both hold onto the their wild card spots while also making a push for their respective division titles between now and the end of the season, it’s just as likely that the desperately hungry Cleveland Indians and Baltimore Orioles bump them out of the playoff picture altogether.

Expect David Price and Jarrod Parker on the mound in the opening game of the weekend series and for the bats to be in full force. The A’s have ridden the quiet contributions of third baseman Josh Donaldson so far this season, while the Rays have been the benefactors of a balanced offensive arsenal led by franchise favorite Evan Longoria.

Considering the American League has shown no shortage of quality World Series contenders, including teams favored on the MLB futures since spring training and earlier, the two clubs featured this weekend face an uphill battle if they want to make good on their championship aspirations.

That may impact some MLB wagering strategies along the way, but it only makes the game that much better. September is here — and this is where good teams become great ones.